Chapter 7: The Vitamins

1
Chapter 7 The Vitamins

• Basic Nutrition
• Dr. Fralinger
• 10/15/07

2
Introduction

• Vitamins
• Organic compounds that are vital to life and
  indispensable to body functions, but are needed
  only in minute amounts
• Noncaloric essential nutrients
• Research hints that two of the major scourges of
  humankind, CVD and cancer, may be linked with low
  intakes of vitamins

3
Introduction

• Geneticists suspect that chronic deficiencies of
  vitamins and minerals may be major contributors
  to genetic damage that can lead to cancer
• Also suspect that vitamin excesses may do the
  same thing

4
Introduction

• The only disease a vitamin will cure is the one
  caused by a deficiency of that vitamin
• Chronic disease prevention evidence still
  emerging

5
Deficiency and classification of vitamins

• Vitamins are essential, noncaloric nutrients that
  are needed in tiny amounts in the diet and help
  to drive cell processes in the body
• The fat-soluble vitamins are vitamins A, D, E,
  and K
• The water-soluble vitamins are vitamin C and the
  B vitamins

6
Deficiency and classification of vitamins

• Precursors, provitamins
• Compounds that can be converted into active
  vitamins once inside the body

7
The Fat-Soluble Vitamins

• Vitamins A, D, E, K
• Found in the fats and oils of foods
• Require bile for absorption
• Once absorbed, they are stored in the liver and
  fatty tissues until the body needs them
• May be toxic in excess

8
The Fat-Soluble Vitamins

• Vitamin A
• First fat-soluble vitamin recognized
• Beta-carotene the plant-derived precursor
• Three forms are active in the body
• Retinol antioxidant
• Retinal
• Retinoic acid

9
The Fat-Soluble Vitamins

• Vitamin A is versatile - has roles in
• gene expression
• Vision
• maintenance of body linings and skin
• immune defenses
• growth of bones and body
• normal development of cells

10
The Fat-Soluble Vitamins

• Vitamin A
• Gene expression
• Help activate or deactivate certain genes and
  affect the production of specific proteins
• Eyesight
• Retina light-sensitive nerve cells lining the
  back of the inside of the eye
• Cornea hard, transparent membrane covering the
  outside of the eye
• Rhodopsin light-sensitive pigment of the cells
  in the retina contains vitamin A

11
Eyesight continued

• Night blindness
• Slow recovery of vision after exposure to flashes
  of bright light at night
• Early symptom of vitamin a deficiency
• Keratin
• Normal protein of hair and nails
• Keratinization
• Accumulation of keratin in a tissue sign of vit.
  A deficiency

12
Eyesight contd

• Xerosis
• Drying of the cornea symptom of vit. A
  deficiency
• Xerophthalmia
• Progressive hardening of the cornea of the eye in
  advanced vit. A deficiency that can lead to
  blindness

13
Fat-Soluble Vitamins

• Vitamin A
• Skin and body linings
• Epithelial tissue
• Serve as selective barriers to environmental
  factors
• Cornea, skin, respiratory tract lining, digestive
  tract lining
• Cell differentiation
• Process by which immature cells are stimulated to
  mature and gain the ability to perform functions
  characteristic of their cell type

14
Fat-Soluble Vitamins

• Vitamin A
• Immunity
• So many of the bodys defenses against infection
  depend on an adequate supply
• Growth
• Assists in growth of bone and teeth
• Deficiency around the world
• Between 3 and 10 million of the worlds children
  suffer from signs of severe deficiency

15
Vitamin A toxicity

• Symptoms include
• Abdominal pain
• Hair loss
• Joint pain
• Stunted growth
• Bone and muscle soreness
• Cessation of menstruation
• Nausea
• Diarrhea
• Rashes
• Damage to liver
• Enlargement of spleen

16
Vitamin A recommendations

• International unit
• Measure of fat-soluble vitamin activity sometimes
  used on supplement labels
• Amount needed is proportional to your body weight
• DRI for man 900 micrograms
• DRI for woman 700 micrograms

17
Food sources of vitamin A

• Foods of animal origin
• Liver
• Fish oil
• Milk and milk products
• Cereals
• Butter
• Eggs
• Vegetables and fruits beta-carotene

18
Vitamin A

• Beta-carotene is an effective antioxidant in the
  body
• Brightly colored plant foods are riches in
  beta-carotene diets containing these foods are
  associated with eye health

19
Vitamin A

• Carotenoid
• Range in color from light yellow to reddish
  orange
• Chemical relatives of beta-carotene
• Retinol activity equivalents (RAE)
• New measure of vit. A activity of beta-carotene
  and other vit. A precursors
• Reflects amt of retinol body will derive from a
  food containing vit. A precursor compounds

20
Vitamin A

• Macular degeneration
• Common, progressive loss of function of the part
  of the retina that is most crucial to focused
  vision
• Degeneration often leads to blindness

21
Vitamin A

• Dietary antioxidants
• Compounds typically found in plant foods that
  decrease adverse effects of oxidation on living
  tissues
• Major are vit. E, C, and beta-carotene

22
Vitamin D

• Raises mineral levels in the blood (calcium
  phosphorus) - bone formation and maintenance
• Deficiency can cause rickets in childhood or
  osteomalacia in later life
• Rickets- Abnormal growth of bone
• Bowed legs or knock-knees
• Outward-bowed chest
• Knobs on ribs
• Osteomalacia overabundance of unmineralized
  bone protein
• Bending of the spine and bowing of the legs

23
Vitamin D

• Most toxic of all the vitamins excesses
  dangerous or deadly
• People exposed to sun make it from a
  cholesterol-like compound in the skin
• Fortified milk is an important food source

24
Vitamin D

• Factors affecting sun exposure and vitamin D
  synthesis
• Air pollution
• City living
• Clothing
• Geography
• Homebound
• Season
• Sunscreen
• Time of day

25
Vitamin E

• Acts as an antioxidant in cell membranes
• Important for integrity of cells exposed to high
  oxygen concentrations (lungs and red white
  blood cells)
• Deficiency rare in human beings, but does occur
  in newborn premature infants

26
Vitamin E

• Widely distributed in plant foods
• Destroyed by high heat
• Toxicity is rare
• Free radicals
• Atoms or molecules with one or more unpaired
  electrons that make it unstable and highly
  reactive

27
Vitamin E

• USDA food guide recommends small daily intakes of
  oils to supply vitamin E
• DRI
• Adults 15 mg/day
• Erythrocyte hemolysis
• Rupture of the RBCs caused by deficiency

28
Vitamin K

• Necessary for blood to clot (Koagulation)
• Deficiency causes uncontrolled bleeding
• Produced by bacterial inhabitants of the
  digestive tract
• Toxicity causes jaundice
• Yellowing of the skin due to spillover of the
  bile pigment bilirubin from the liver into the
  general circulation

29
Vitamin K

• DRI
• Men 120 ug/day
• Women 90 ug/day

30
Vitamin C

• Antioxidant
• Helps to maintain collagen (protein of connective
  tissue
• Protects against infection
• Helps in iron absorption
• Cold or cancer prevention not well supported by
  research
• Ample amts can be obtained from foods

31
Vitamin C

• Scurvy
• Vitamin C-deficiency disease
• Ascorbic acid
• One of the active forms of vit. C
• Collagen
• Chief protein of most connective tissues,
  including scars, ligaments, tendons, underlying
  matrix of teeth
• Prooxidant
• Compound that triggers reactions involving oxygen

32
Vitamin C

• DRI
• Men 90 mg/day
• Women 75 mg/day
• Smokers - 35 mg/day

33
The B Vitamins in Unison

• Tender Romance Never Fails with 60 or 12
  Beautiful Pearls
• Thiamin, Riboflavin, Niacin, Folate, B6 and B12,
  Biotin, Pantothenic acid
• Act as coenzymes
• Small molecules that work with enzymes to promote
  their activity

34
B Vitamin Roles in Metabolism

• Help body metabolize carbs, lipids, and amino
  acids
• Help the body use the energy-yielding nutrients

35
B Vitamin Deficiencies

• If they are present, they are not felt
• Only when they are absent do we feel it
• Deficiencies lead to

36
B Vitamins

• As part of coenzymes, help enzymes do their jobs
• Facilitate the work of every cell
• Some help generate energy
• Others help make protein and new cells
• Work everywhere in the body tissue to metabolize
  carbs, fat and protein

37
B Vitamins as Individuals

• Thiamin
• Involved in the bodys use of fuels
• Beriberi
• Thiamin-deficiency disease
• Characterized by
• loss of sensation in the hands and feet
• muscular weakness
• advancing paralysis
• abnormal heart action

38
B Vitamins as Individuals

• Riboflavin
• Active in the bodys energy-releasing mechanisms
• Niacin
• Needed in energy metabolism
• Can be eaten preformed or can be made in body
  tryptophan
• Pellagra
• Niacin-deficiency disease
• Symptoms are the 4 Ds diarrhea, dermatitis,
  dementia, and death

39
B Vitamins as Individuals

• Niacin equivalents (NE)
• Amt of niacin present in food, including the
  niacin that can theoretically be made from its
  precursor tryptophan present in the food
• Folate
• Acts as part of a coenzyme important in the
  manufacture of new cells
• Form added to foods and supplements is folic acid

40
B Vitamins as Individuals

• Neural tube defects
• Abnormalities of the brain and spinal cord
  apparent at birth
• believed to be related to womans folate intake
  before and during pregnancy
• Dietary folate equivalent
• Unit of measure expressing the amt of folate
  available to the body from naturally occurring
  sources

41
B Vitamins as Individuals

• Vitamin B12
• Helps to convert folate to its active form
• Helps maintain the sheath around nerve cells
• Intrinsic factor
• Factor found inside a system
• Pernicious anemia
• B12 deficiency disease
• Caused by lack of intrinsic factor
• Characterized by large, immature RBC damage to
  the nervous system

42
B Vitamins as Individuals

• Vitamin B6
• Needed in protein metabolism
• Plays roles in synthesis of hemoglobin and
  neurotransmitters
• Assists in conversion of amino acid tryptophan to
  serotonin
• Serotonin
• Important in sleep regulation, appetite control,
  mood regulation

43
B Vitamins as Individuals

• B6 contd
• Carpal tunnel syndrome
• Piched nerve at the wrist, causing pain or
  numbness in the hand
• Often caused by repetitive motion of the wrist

44
B Vitamins and Heart Disease

• Homocysteine
• Amino acid produced as an intermediate compound
  during amino acid metabolism
• Buildup in blood associated with deficiencies of
  folate other B vitamins - may increase risk of
  disease
• Biotin
• Coenzyme necessary for fat synthesis and other
  metabolic reactions
• Panthothenic acid
• B vitamin important in energy metabolism

45
Non-B vitamins

• Choline is needed in the diet, but it is not a
  vitamin and deficiencies are unheard of outside
  the lab.
• May other substances that people claim are B
  vitamins are not (carnitine, inositol, lipoic
  acid)

46
Non-B vitamins

• Choline
• Nonessential nutrient used to make the
  phospholipid lecithin and other molecules
• Carnitine
• Nonessential nutrient that functions in cellular
  activities
• Inositol
• Nonessential nutrient found in cell membranes
• Lipoic acid
• Nonessential nutrient